Alcohol: the facts

A drink or two a day is good for you. It protects against heart disease, strokes and perhaps some forms of gallstones. But at higher levels it causes a variety of worrying long-term health problems.

After much research, nutritionists have set safe drinking limits at 14 units a week for women and 21 for men. A unit is equivalent to one glass of wine, or half a pint of beer, or a single pub measure of spirits.

Although women generally drink less than men, the consequences of drinking too much are more serious for them. This is because women's bodies have far more fat and less water than men and concentrations of alcohol are therefore higher than in men of equal height and weight. That men are usually taller and heavier, compounds the problem.

Here's how alcohol affects your body and your general health.

Heart. When drinking exceeds the recommended guidelines, it starts to increase a person's risk of heart disease. A British study showed that women consuming 14 units or fewer of alcohol a week had reduced risk of cardiovascular disease, but those drinking more than 15 units were twice as likely to have hypertension or high blood pressure, which is believed to increase the risk of heart disease.

The study also found that alcohol raised unhealthy (low-density lipoprotein) cholesterol levels in the blood. The risk of a heart attack within ten years was lowest among those consuming seven units a week or fewer.

Weight. Alcohol is second only to fat itself in the number of calories it carries per gram. A glass of dry white wine contains 85 calories, and sweet wine 120 calories. A pint of beer has 170 calories, and stronger lagers contain up to 400 calories per pint.

Even if you stick to the recommended limit, you can easily consume an extra 6,500 calories per month. This equates to a monthly weight gain of two to three pounds.

Liver. Over time, the liver learns to break down alcohol at a faster rate, which is why it takes progressively more alcohol to get you drunk. But this process produces toxic chemicals that can attack the liver and cause cirrhosis.

Prolonged heavy drinking also upsets the delicate balance of enzymes in the liver and, eventually, fatty globules develop that cause the liver to swell.

Pancreas. A painful inflammation of the pancreas, known as pancreatitis, can occur after just a few weeks of heavy drinking. It results in a swollen abdominal area and can cause nausea and vomiting.

Mental health. Alcohol suppresses the nervous system, which is why people lose their inhibitions and feel uplifted in the short-term. However, it is a depressant and also shuts off the parts of the brain controlling judgment. In the long-term, it can cause depression, anxiety and lethargy.

Breast cancer. A review of research published in the U.S. found that a high intake of alcohol is definitely associated with an increased risk of breast cancer in women. Those found to be at most risk were women who drank, on average each day, either 2.3 to 4.5 bottles of beer, or 2.8 to 5.6 glasses of wine, or two to four shorts.

Nutrient loss. Alcohol lacks essential vitamins and minerals. Even Guinness and stouts, which people think contain a lot of iron, are very low in mineral content. As a result, people who drink heavily are at risk of nutritional deficiencies, especially from thiamin, vitamin B, calcium, magnesium and zinc. Because drinking too affects the liver, it impairs its ability to store the fat-soluble vitamins A, D, E and K and to metabolise protein.

Fertility and pregnancy. Women drinking only up to five units of alcohol per week are twice as likely to conceive as those who drink ten units or more. It is thought that too much alcohol interferes with the fertilised egg's ability to implant in the womb.

Several studies have shown that babies born to women who drink while pregnant are more at risk of brain damage and learning disabilities. American scientists have found that alcohol can cause millions of brain cells in the foetus to die. These cells are responsible for connections needed for memory, learning and thought. One drinking binge of four hours or more can be enough to cause damage. Another risk is foetal alcohol syndrome, caused by overexposure to alcohol in the womb.

Cancer. People who drink between seven and 21 units of spirits a week (as opposed to wine) double their likelihood of getting cancer of the digestive tract compared to teetotallers.

Skin. Dilated capillaries, caused by blood rushing to the surface of the skin, is a common side-effect of heavy drinking. Your complexion can also become more prone to spots, and may develop dry patches.